1. Field of the Invention
The present invention is related to electrical connectors, and more particularly is directed towards a new and improved modular jack adapted to serve as an interface between a standard modular plug and a printed circuit board.
2. Description of the Related Art
In recent years, a great deal of research and development has gone into providing miniature plugs and connectors for low voltage electronic applications. For example, in the telephone industry, increasing use is being made of modular plugs and connectors on the cords, base, handset and wall terminal block of a telephone system. Typical miniature plugs are described, for example, in U.S. Pat. Nos. 3,954,320 and 3,998,514, both in the name of Hardesty.
It is desirable that such plugs and connectors be of rugged construction, compact size and high reliability, without requiring excessive manufacturing cost. Such plugs and connectors must also be able to be reliably, rapidly and automatically terminated to cable and equipment components, respectively.
While the plugs and connectors provided in the past have been generally satisfactory, they suffer from one or more material drawbacks. For example, the miniature connector described in U.S. Pat. No. 3,850,497 is generally a rugged and compact unit. However, the complexity of the contact wire assembly utilized in the housing of the connector results in a high manufacturing cost because of the many components which must be assembled in a precision arrangement. Additionally, the interconnect portions of the contact wire assembly which protrude from the rear of the connector housing consist of flexible jumper wires which have spade terminals or solder tabs for making connections to equipment components. Such terminals or tabs must be manually anchored or set in position for making the desired electrical connections. This procedure results in high labor costs when such connectors are mounted, for example, on printed circuit boards or to their electronic or telephone components. A similar connector is described in U.S. Pat. No. 3,990,764, but suffers from the same deficiencies just described.
The aforedescribed connectors also suffer from an additional major drawback. Regulations governing the size and spacing of standardized plugs have been adopted by the Federal Communication Commission. Consequently, any connector designed to mate with such plugs must have corresponding spacing between adjacent contact wires. However, printed circuit boards (hereafter "PCBs") which are utilized extensively, for example, in digital data transmission equipment, sensing systems and the like, are presently manufactured with an industry-wide standard for conductor pad spacing that is different from the contact spacing on the above-described miniature telephone plugs and connectors. As a result, with these components, it has been necessary in the past to provide jumper wires or a special cable to connect the standard miniature telephone connector or jack with a PCB.
In my pending U.S. patent application Ser. No. 120,846, filed Feb. 12, 1980 (a continuation application of Ser. No. 915,457, filed June 14, 1978), I set forth a novel electrical connector particularly adapted to serve as a direct interface between a standard miniature telephone plug and a printed circuit board, thereby eliminating the need for labor intensive jumper wires or special cables. The connector described in my prior applications includes a plurality of conductors formed in the connector housing, one end of each of the conductors extending from the rear portion of the housing in an alternating, staggered fashion so as to mate with correspondingly spaced apertures (about which the conductor pads are formed) in a printed circuit board. The conductors extend through the body of the housing to the front portion thereof and are then bent rearwardly into a plug-receiving opening so as to form spring contact portions which are laterally spaced so as to correspond with the contact terminal spacing of the mating plug. It is essential in this design, to facilitate plug mating and attachment of the connector to the printed circuit board for subsequent wave soldering, that there exists a differential spacing between the contact portions of the conductors that extend rearwardly into the connector opening and the alternating staggered portions of the conductors which extend perpendicularly from the rear portion of the connector. More particularly, a common PCB spacing requires adjacent conductor apertures to be spaced 0.050 inch apart, while the Federal Communications Commission requires 0.040 inch spacing between the spring contact portions of corresponding adjacent conductors.
Several United States Patents set forth a miniature connector for directly interfacing a modular plug with a printed circuit board. More particularly, U.S. Pat. Nos. 4,193,654 and 4,221,458 each set forth a connector housing wherein the spring contact portions extend over an outside wall of the connector housing to be subsequently bent rearwardly into the opening to form the spring contact portions. The other ends of the conductors extend from the housing in alternating rows so as to allegedly be matable with the apertures in a printed circuit board; however, no differential spacing is provided between the spring contact portions and the PCB matable portions of the conductors.
U.S. Pat. No. 4,210,376 sets forth a connector similar in concept to the above-described patents, but which does take into account the necessary differential spacing required between the spring contact portions and the PCB-terminable portions of the conductors (See FIG. 6). However, the connector structure described in this patent still necessitates a relatively long strip of stamped conductor to be utilized since the conductors are wrapped around the outside wall of the connector from the rear to the front and are bent back into the connector opening so as to form the spring contact portions.
The length of the conductors required for such connectors involves a considerable component cost, inasmuch as such conductors must generally be plated with a precious metal to meet industry standards regarding reliability, longevity and electrical contact integrity. The precious metal may comprise, for example, gold, and it therefore may be appreciated that it would be highly desirable to provide an improved connector which could utilize conductors of considerably reduced lengths over previous designs.
The gold plated spring contact portions of presently known connectors are bent rearwardly into the plug-receiving opening of the connector housing at a fixed angle which achieves the contact pressure required with the terminals of the mating plug to maintain industry standards of conductivity, wear and reliability. If the contact pressure could somehow be increased, it might be possible to use less precious plating metals having a lower conductivity, thereby further reducing the cost of the conductor.
It is also evident from U.S. Pat. No. 4,210,376 that the conductors thereof comprise stamped strips which include integrally formed barbs along the length thereof which act to retain each conductor within channels or slots formed in the housing. The use of such stamped conductors, while not unacceptable, requires special forming and cutting machinery, and can result in more material waste when compared to the use of standard round conductor wires. It would therefore appear that if means could be provided in the connector housing for retaining standard conductor wires, it would be an improvement over the barbed flat conductor strips evident from this patent.
During use of such a connector, it may be necessary to short together two of the conductors in the connector when the mating plug is removed. This occurs, for example, when the printed circuit requires a circuit path to be closed in certain applications in the absence of the mating plug. It would therefore be desirable to be able to provide an improved connector wherein means are provided for automatically shorting two or more conductors when the mating plug is not inserted into the connector.
Certain applications where printed circuit boards are utilized require a closely-spaced array of parallel PCBs. If one or more boards require a modular connector of the type discussed above, it is important that the height of the connector be made as small as possible, in order that the overall circuit board array will take up as little space as practicable. Presently available connectors, however, have not been designed with much thought to such a requirement. It would therefore be very desirable if a low profile connector of the type described could be provided which permits use of the connector with very closely spaced printed circuit boards in a space-economical fashion.
It is towards achieving these advantages and overcoming the noted deficiencies of the state of the art connectors that the present invention is advanced.